Transcriptome analysis of the challenged gut barrier in rats : mucosal response to Salmonella and Fructo-oligosaccharides

De darmbarrière is een complex systeem dat het lichaam beschermt tegen schadelijke stoffen en pathogenen die met het voedsel binnenkomen. Om beter inzicht te krijgen in de biologische processen die zorgen voor de barrièrefunctie van darmcellen hebben we in een levend organisme, de rat, bestudeerd hoe deze reageren op twee verschillende stoffen die stress van de darmbarrière veroorzaken: het veel voorkomende voedselpathogeen Salmonella en het voedingsmiddel Fructo-oligosaccharides (FOS). Dit hebben we gedaan met zogenaamde whole genome transcriptoom (genexpressie) analyse, waarmee de activiteit van nagenoeg alle genen tegelijkertijd kwantitatief bepaald kan worden. Ons onderzoek is een van de eerste studies die de moleculaire effecten van een Salmonella infectie op darmcellen van een levend dier heeft onderzocht. Het bleek, tegen de verwachting in, dat Salmonella niet alleen een effect heeft op dunne darm cellen, maar ook op dikke darm cellen. Verder hebben we gevonden dat celkweek modellen, die tot nu toe veel gebruikt zijn voor infectieonderzoek , slechts in zeer geringe mate voorspellend zijn voor de effecten in het dier. Met de genexpressie analyse hebben we niet alleen nieuwe darmbarrière processen gevonden, maar ook nieuwe mogelijke biomarkers die gebruikt kunnen worden om de darmgezondheid te meten in interventie proeven met mensen of dieren. Een voeding met FOS verhoogt de doorlaatbaarheid van de darmwand en verergert de infectie met Salmonella. Dit ging gepaard met verhoogde expressie van genen die betrokken zijn bij de weerstand of afweer. Dit betekent dat verhoging van deze weerstand markers voorzichtig geïnterpreteerd moet worden en niet per definitie een gunstige situatie (verhoogde weerstand) weerspiegelt. Het heeft de voorkeur om weerstand markers altijd te koppelen aan meetbare en eenduidige eindpunten zoals passage van de bacteriën door de darmwand. Tenslotte hebben we sterke aanwijzingen verkregen dat een ontregeld energie metabolisme in darmcellen de onderliggende oorzaak is van de verhoogde doorlaatbaarheid van de darmwand en verminderde weerstand door FOS consumptie. Ons onderzoek heeft vele nieuwe inzichten opgeleverd in mechanismen die een rol spelen in de barrière functie van de darm en vormt de basis voor verder onderzoek naar voedingsmiddelen die de darmbarrière kunnen versterken

Ileal Mucosal and Fecal Pancreatitis Associated Protein Levels Reflect Severity of Salmonella Inflection in Rats

Background Microbial infections induce ileal pancreatitis-associated protein/regenerating gene III (PAP/RegIII) mRNA expression. Despite increasing interest, little is known about the PAP/RegIII protein. Therefore, ileal mucosal PAP/RegIII protein expression, localization, and fecal excretion were studied in rats upon Salmonella infection. Results Salmonella infection increased ileal mucosal PAP/RegIII protein levels in enterocytes located at the crypt-villus junction. Increased colonization and translocation of Salmonella was associated with higher ileal mucosal PAP/RegIII levels and secretion of this protein in feces. Conclusions PAP/RegIII protein is increased in enterocytes of the ileal mucosa during Salmonella infection and is associated with infection severity. PAP/RegIII is excreted in feces and might be used as a new and non-invasive infection marke

Transcription profiling of rat ileum mucosa and Peyers patches in the small intestine at different time points following Salmonella infection

Time dependent effect of Salmonella infection on host gene expression in vivo in the ileum mucosa and Peyer’s patches

Transcription profiling of rat ileum mucosa and Peyers patches in the small intestine at different time points following Salmonella infection

Time dependent effect of Salmonella infection on host gene expression in vivo in the ileum mucosa and Peyer’s patches

Gene expression changes in cecum mucosa upon dietary treatment

To increase our knowledge of the effects of Fructo oligosaccharides (FOS) on the intestinal barrier function in rats, a controlled rat infection study was performed. Two groups of rats (n=12 per group) were adapted to a diet with or without FOS. mRNA was collected from the mucosa of the cecum and changes in gene expression were assessed using an agilent rat whole genome microarray (G4131A Agilent Technologies). Results indicate that dietary FOS influences immune response and wound healing mechanisms, which will most likely affect the intestinal barrier

Colonic gene expression upon dietary treatment

To increase our knowledge of the effects of Fructo oligosaccharides (FOS) on the intestinal barrier function in rats, a controlled rat infection study was performed. Two groups of rats were adapted to a diet with or without FOS. mRNA was collected from the mucosa of the colon and changes in gene expression were assessed using an agilent rat whole genome microarray (G4131A Agilent Technologies). Results indicate that dietary FOS influences energy metabolism, which will most likely play a role in the effects of FOS on the intestinal barrier

Transcription profiling of rat colonic mucosa at different time points following Salmonella infection

Salmonella enteritidis is suggested to translocate in the small intestine. Previously we identified that prebiotics, fermented in the colon, increased Salmonella translocation in rats, suggesting involvement of the colon in translocation. Effects of Salmonella on colonic gene expression in vivo are largely unknown. The aim of this study was to characterize time dependent Salmonella induced changes of colonic mucosal gene expression in rats using whole genome microarrays. Rats were orally infected with Salmonella enteritidis to mimic a foodbore infection and colonic gene expression was determined at day 1, 3 and 6 post-infection (n=8 per timepoint). Agilent rat whole genome microarray (G4131A Agilent Technologies) were used. Results indicate that colon is clearly a target tissue for Salmonella considering the abundant changes in mucosal gene expression observed

Transcription profiling of rat colonic mucosa at different time points following Salmonella infection

Salmonella enteritidis is suggested to translocate in the small intestine. Previously we identified that prebiotics, fermented in the colon, increased Salmonella translocation in rats, suggesting involvement of the colon in translocation. Effects of Salmonella on colonic gene expression in vivo are largely unknown. The aim of this study was to characterize time dependent Salmonella induced changes of colonic mucosal gene expression in rats using whole genome microarrays. Rats were orally infected with Salmonella enteritidis to mimic a foodbore infection and colonic gene expression was determined at day 1, 3 and 6 post-infection (n=8 per timepoint). Agilent rat whole genome microarray (G4131A Agilent Technologies) were used. Results indicate that colon is clearly a target tissue for Salmonella considering the abundant changes in mucosal gene expression observed

Colonic gene expression upon dietary treatment

To increase our knowledge of the effects of Fructo oligosaccharides (FOS) on the intestinal barrier function in rats, a controlled rat infection study was performed. Two groups of rats were adapted to a diet with or without FOS. mRNA was collected from the mucosa of the colon and changes in gene expression were assessed using an agilent rat whole genome microarray (G4131A Agilent Technologies). Results indicate that dietary FOS influences energy metabolism, which will most likely play a role in the effects of FOS on the intestinal barrier

Colonic gene expression upon Salmonella infection and dietary treatment

To increase our knowledge of the effects of Fructo oligosaccharides (FOS) on Salmonella infection in fats, a controlle rat infection study was performed. Two groups of 12 rats were adapted for 14 days to a cellulose diet and one group of 12 rats to a FOS diet. One cellulose-fed group and the FOS-fed group were infected with Salmonella. Two days post infection mRNA was collected from the mucosa of the colon and changes in gene expression were assessed using an Agilent rat whole genome microarray (G4131A Agilent Technologies). Results indicate that Salmonella affects colonic mucosal gene expression, which is further enhanded by dietary FOS